The advertisement leaves little doubt about the strength of the Professor's powers. 'Your partner left you? She/he will be back and follow you like a dog obeys his master. Fast results.' Another aims to comfort those who fear they have been cursed, offering to 'break all types of black magic or witchcraft' while a third promises assistance with 'evil bothering'.

Although advertisements for psychics and tarot readers now appear in almost every newspaper, the spiritualists or 'marabouts' who aim their services at members of Britain's African community stand out because of the sheer bravado of their claims - demonic forces, infertility, business difficulties, immigration problems, weight loss and general bad luck can all be dealt with and results are guaranteed, apparently.

None of those contacted by The Observer yesterday was willing to speak on the record about their work but the sheer number of practitioners - they fill an entire page in the weekly newspaper, the Voice , indicates there is a substantial market for their services.

On Friday, the issue of spiritual belief within the African community was highlighted once more when Sita Kisanga and her brother Sebastian Pinto were found guilty at the Old Bailey of aiding and abetting the physical abuse of an eight-year-old girl. The girl's aunt, who cannot be named for legal reasons, was convicted of child cruelty. The court heard that the child, who was brought to Britain from Angola by her aunt after her parents died, had been beaten, cut and had chilli peppers rubbed in her eyes to 'beat the devil out of her'.

Kisanga, 35, accused alongside the child's 38-year-old aunt, and Pinto, 33, attended a Combat Spirituel church in Dalston, east London. The church belongs to a fundamentalist wing of Christianity and is believed to be one of at least 300 in the UK, mostly in London and mostly supported by people who originated from west Africa.

Many such churches sanction aggressive forms of exorcism involving physical contact with the possessed subject, though the Pastor at Combat Spirituel told police he did not condone the actions of Kisanga and the others.

Dr Richard Hoskins, an expert on African religions who gave evidence at the trial, told The Observer that these so-called 'breakaway churches' have much in common with other evangelical institutions. 'The services are usually exuberant and energetic. The congregation do not meet in a traditional church building. Instead they come together in a garage or someone's home.

'The key difference takes place when it comes to the practice of exorcism and it is here that potential abuse can occur. There will be shouting and the person being exorcised will often have convulsions. It is a lengthy process that can go on for hours. Another problem is that there seem to be two elements driving those at the head of these churches. One is money, the other is power and, unfortunately, these are opposing forces.'

Kisanga denied she had taken part in the beatings of the girl and said that she had tried to stop the abuse by the child's aunt. But she admitted that like the aunt she had believed that the girl was 'kendoki' - a witch.

'In our community, kendoki is killing people,' she said in an interview broadcast by Radio 5 Live yesterday. 'It is doing bad things. In our community in the UK everyone believes in it. In our country they believe in it too. Kendoki is something that you have to be scared of because, in our culture kendoki can kill you and destroy your life completely. Kendoki can make you barren, sometimes kendoki can ruin your chances of staying in this country.'

The case has striking similarities with that of Victoria Climbié, also eight, who was beaten, burnt with cigarettes and forced to sleep in a bin liner inside an empty bath. She died in hospital in February 2000, suffering from hypothermia and malnutrition.

Both girls were brought to Britain from Africa by aunts claiming them as their own daughters and they were both mistreated, starved and traumatised after their guardians said they were possessed by the devil. In Victoria's case, she was taken to various spiritual churches where the congregations were asked to pray for her after she began throwing her faeces around in protest at her treatment.

Her plight was overlooked by police, social workers and medical staff and she died covered in bruises. Her great-aunt and her boyfriend were convicted of her murder and jailed for life at the Old Bailey. Two social workers dealing with her case were sacked. Social workers have also been criticised in the current case as the girl was briefly taken into care but later returned to her family.

The latest girl's ordeal also has echoes of the mystery of the dismembered body of a boy named 'Adam' by police who was found in the River Thames in September 2001 and is thought to have been the victim of a ritual killing. The Metropolitan Police says there is nothing to link the cases but officers are worried that they have not been able to trace 300 African boys who disappeared from London schools.

In response to the Kisanga case the Met has set up a project to combat some of the wilder claims of 'witchcraft' in African communities in the UK. Dubbed Project Violet, the scheme aims to prevent and detect ritualistic, faith-related child abuse, by engaging with African communities, initially in the east London boroughs of Newham and Hackney.

Detective Superintendent Chris Bourlet, deputy head of the Met's Child Abuse Investigation Command, said: 'Project Violet is going to look at ways of supporting communities and seeking ways of preventing this kind of abuse in the future. We have no idea of the scale of the problem because up to now, we have not always recorded the purpose of the abuse. How prevalent it is, we have still to find out.'

During the trial the court heard that the girl's aunt had an IQ that put her in the bottom one per cent of the population and was 'gullible and easily led'.

According to Debbie Ariyo, director of Africans Unite Against Child Abuse, part of the blame lies with the churches who endorse such extreme beliefs. 'If a child is accused of being a witch and that accusation is endorsed by the church, it gives people leeway to perpetrate abuse on that child. Either directly or indirectly, if a church confirms someone's status as a witch, they are condoning abuse.'

Leading theologian Dr Robert Beckford, who presented the controversial Channel 4 documentary God is Black , told The Observer that he is greatly disturbed by the way African beliefs are being portrayed as a result of the case. 'First of all we have to draw a clear line between biblical exorcism, which does not involve any kind of physical contact, and child abuse, which unfortunately does,' he said. 'From a purely theological point of view, what they did was wrong. Nowhere in the Bible does it say that if someone is possessed with a demon, you have to beat it out of them. This was clearly a case of child abuse and no one in their right mind would ever condone that.

'Yet at the same time, some of the coverage reminds me of the racist 19th-century anthropological literature. West Africans are not the only people who believe in demonic possession or the existence of evil spirits. The Anglican church believes in those things too and so does the Evangelical Alliance. The attitude seems to be that if the people supporting the beliefs have PhDs then they are sensible but if they are working class people from Africa then they must be mad.'

The girl at the centre of the case is now 10 years old and living with foster parents and is outwardly thriving, but her mental scars are still there. According to detectives, she is still traumatised by her experience and the mere mention of witchcraft sends her into floods of tears.